Molecular mechanisms of action are studied in parotid gland acinar cells to determine regulatory events associated with protein exocytosis. In addition to standard biochemical, immunological and morphological methods recently developed experimental techniques such as photoaffinity labelling (8-azido cyclic (32P)-AMP), enzyme linked immunosorbent antibody technique (ELISA) and microscopic examination of subcellular fractions are part of the experimental design. Cellular responses to receptor interactions of parotid cells with Beta-agonists have been studied using measurements of cyclic AMP-dependent protein kinase as an index. The majority of the enzyme activity (more than 60% of the total) is extra-nuclear and the remainder is in the nucleus. In response to stimulation with isoproterenol cyclic AMP-dependent protein kinase activity is increased in the cytoplasmic particulate fraction which consists largely of granules. Redistribution of protein kinase isozymes occurs after stimulation (type 1 appears in the cytosol whereas only type II is present in controls).